Electrical transformers having dismantlable laminated cores



ELECTRICAL TRANSFORMERS HAVING DISMANTLABLE LAMINATED CORES Filed Feb. 2, 1961 F. W. GEE

March 2, 1965 2 Sheets-Sheet 1 Inventor v 6 am! M ,7

J Attorney;

' March 2, 1965 F. w. GEE 3,

ELECTRICAL TRANSFORMERS HAVING DISMANTLABLE LAMINATED CORES Filed Feb. 2 1961 2 Sheets-Sheet 2 //b /2b //b' lZb //b F/GS.

Inventor FI w. Gas.

Attorneys Jaw.

United States Patent 3,172,067 ELECTRICAL TRANSFORMERS HAVING Di MANTLABLE LAMINATED CORES Frank W. Gee, Manchester, England, assignor to Ferranti, Limited, Hollinwood, England, a company of Great Britain and Northern Ireland Filed Feb. 2, 1961, Ser. No. 86,757 Claims priority, application Great Britain, Feb. 9, 1960, 4,466/ 60 Claims. (Cl. 336-217) This invention relates to electrical transformers with laminated cores.

The invention has particular application to transformers which are large enough considering the situation of the site and the conditions of access to it to be not readily transportable to the site when fully assembled. In such cases it is known to dismantle the transformer at the manufacturers works and transport the windings, core laminations, and core framework separately and reassemble them on site. This procedure nevertheless presents further difiiculties where the tackle available is limited, which is usually the case on such sites.

An object of the present invention is to provide a large transformer having a laminated core arranged to facilitate transport to and installation on site.

Another object is to provide such a transformer the core of which may be dismantled and reassembled with less difficulty and with less detriment to the transformers ultimate performance than is possible with such cores as hitherto disclosed.

In accordance with the present invention, there is provided an electrical transformer having a laminated core which includes at least one planar plate frame member of non-magnetic material formed by vertical leg components, at least one upper yoke component, and at least one lower yoke component, the upper end of each leg component having a portion which closely interlocks with a complementary portion at the adjacent end of the adjacent upper yoke component, leg laminations permanently secured to said leg components leaving accessible the said interlocking portions of those components, upper yoke laminations detachably secured to each upper yoke component, at least prior to final assembly on site, and interleaving With said leg laminations at the junctions thereof in such manner as to permit dismantling of the core, and lower yoke laminations secured to each lower yoke component and interleaving with said leg laminations at the junctions thereof.

The lower end of each leg component may have a porion which closely interlocks with a complementary portion at the adjacent end of the adjacent lower yoke component, the said lower yoke laminations being detachably secured to the yoke component, at least prior to final assembly on site, and interleaving with said leg laminations at the junctions thereof in such manner as to permit further dismantling of the core.

In the accompanying drawings, in which similar components are indicated by corresponding reference numbers,

FIGURE 1 shows a three-phase transformer core according to one embodiment of the invention, with the core dismantled for transit,

FIGURE 2 is a plan view of the core of FIGURE 1 after assembly,

And FIGURES 3 to 5 are plan views of a core in accordance with further embodiments.

In carrying out the invention in accordance with one form by way of example, a laminated core for a threephase transformer, see the accompanying drawings, includes a planar plate frame member of non-magnetic material-conveniently, stainless steel--having three vertical leg components 11 and upper and lower yoke components 12 arranged for assembly to form the composite frame by means of male portions 12 of the yoke components designed to closely interlock with complementary female portions 11 of the leg components. By planar plate is meant that each component is in the form of a flat strip or plate thick enough to give the composite frame member the required strength and rigidity. The major surfaces on each side of the yoke components on assembly are co-planar with the corresponding surfaces of the leg components-see FIG. 2so that the composite frame is in the form of a thick flat rectangular plate, suitable for being sandwiched centrally between the laminations, with two rectangular windows.

During the construction of the core in the manufacturers works the leg laminations 13 are permanently secured to both sides of the leg components 11 of the frame, leaving accessible the interlocking portions 11 Arrangements are made for detachably securing the yoke laminations 14 to both sides of the yoke components 12. All the laminations are designed in the usual manner so that the yoke laminations interleave with the leg laminations at the junctions between them.

To allow the transformer to be tested in the manufacturers works, the leg components of the core with the laminations secured to them as shown in FIGURE 1 are threaded through the windings (not shown). The core is then assembled by attaching the yoke components 12 to the leg components 11 by means of their interlocking portions 12 and 11 As will be evident from FIGURE 1, the interlocking connections are such that the portions 12' and 11 lie within the boundary planes of the assembled frame and secure the yoke and leg components against separation from one another in directions parallel to said planes whilst permitting their separation by relative movement in a direction perpendicular thereto. This process completes the frame of the core and imparts to the leg components their predetermined relative positions.

The next step is to add the top and bottom yoke laminations 14, by insertion downwards and upwards, respectively, to interleave with the leg laminations and, at the centre leg, with one another.

Finally, the yoke laminations are detachably secured to the respective yoke components, by bolting them to the yoke component or securing them in position by bands, whichever is convenient.

After test, the transformer is dismantled for transit by reversing the above steps-namely, removing the yoke laminations, detaching the yoke components of the frame from the leg components, and withdrawing the leg component and their permanently secured laminations from the windings. Even transformers of the largest size may thus be reduced to parts small enough to be readily transportable to sites of considerable inaccessibility.

On site the transformer is re-assembled in the steps first described, which present little difliculty, even with comparatively simple tackle. If subsequent dismantling is not required, the yoke laminations, when in position, may be permanently secured to the yoke components rather than detachably secured.

It will readily be appreciated that the frame acts also as a built-in jig to ensure assembly of the core to the exact requirements.

The use of interlocking portions, rather than a bolting method, to secure the frame components together results in a frame which requires no modification of the laminations in the vicinity of the frame joints. The small cross-sectional area of the frame and the use for it of a non-magnetic (that is, low permeability) material cause the self-heating of the frame and the losses contributed by it to the core to be negligible. Thus the advantage which this construction possesses of allowing ready dismantling and reassembly to exact requirements is obtained without appreciable detriment to the transformers ultimate performance.

The frame member need not necessarily take the exact form described. In some constructions, for example, the frame, instead of being sandwiched centrally between the laminations as shown in FIG. 2, may have the laminations secured to one side only of the frame, as shown in FIG. 3. Or the frame may be in two planar members 11a, 12a, and 11b, 12b, parallel to each other, each frame member being as described above with reference to FIG. 1, with all the laminations sandwiched between them, as shown in FIG. 4. For extra strength this last construction may include a central frame 110, 120, similar to that of FIG. 2, making three parallel planar members as shown in FIG. 5. I

Where it is required to separate only the windings from the core, only the upper yoke components need be made separable as described, the lower yoke components and their laminations being permanently secured to the leg components and laminations during the original manufacture. The lower yoke components may thus be made in one piece with the leg components of the frame.

The invention is also applicable to other than threephase transformers-for example, to single-phase transformers, where the core has two legs and single upper andlower yokes.

What I claim is:

1. An electrical transformer having a laminated core of the type adapted to be dismantled for transportation to and reassembled at the site of use including at least one rigid planar plate frame member of nonmagnetic material comprising a plurality of vertical leg components, at least one upper yoke component, and at least one lower yoke component, each of said components consisting of a flat plate of substantial thickness sufficient, when assern bled with other components, to form a rigid planar plate frame of uniform thickness, the upper and lower ends of each leg component being secured to the adjacent ends of the upper and lower yoke components, respec- 4 tively, the upper end of each leg component having a portion which is adapted to separably interlock with a complementary portion at the adjacent end of the adjacent upper yoke component, each pair of complementary interlocking portions of said components lying within the planes of the plate surfaces of said frame and being separable only by relative movement in a direction perpendicular to said planes, leg laminations permanently secured to said leg components and so formed as to leave accessible the said interlocking portions of said components, upper yoke laminations detachably secured to each upper yoke component and interleaving with said leg laminations at the junction thereof, and lower yoke laminations secured to each lower yoke component and inter leaving with said leg laminations at the junctions thereof.

2. A transformer as claimed in claim 1 wherein the lower end of each leg component has a portion which is adapted to separably interlock with a complementary portion at the adjacent end of the adjacent lower yoke component, and the said lower yoke laminations are detachably secured to the lower yoke components.

3. A transformer as claimed in claim 1 wherein the frame member is sandwiched centrally between the laminations.

4. A transformer as claimed in claim 1 wherein the core includes two frame members having the laminations sandwiched between them.

5. A transformer as claimed in claim 1 wherein the laminations are secured to one side only of the frame member.

References Cited by the Examiner UNITED STATES PATENTS 2,702,375 2/55 Johnson 336-210 FOREIGN PATENTS 550,191 12/42 Great Britain.

JOHN F. BURNS, Primary Examiner.

MILTON O. HIRSHFIELD, E. JAMES SAX,

Examiners, 

1. AN ELECTRICAL TRANSFORMER HAVING A LAMINATED CORE OF THE TYPE ADAPTED TO BE DISMANTLED FOR TRANSPORTATION TO AND REASSEMBLED AT THE SITE OF USE INCLUDING AT LEAST ONE RIGID PLANAR PLATE FRAME MEMBER OF NONMAGNETIC MATERIAL COMPRISING A PLURALITY OF VERTICAL LEG COMPARTMENTS, AT LEAST ONE UPPER YOKE COMPONENT, AND AT LEAST ONE LOWER YOKE COMPONENT, EACH OF SAID COMPONENTS CONSISTING OF A FLAT PLATE OF SUBSTANTIAL THICKNESS SUFFICIENT, WHEN ASSEMBLED WITH OTHER COMPONENTS, TO FORM A RIGID PLANAR PLATE FRAME OF UNIFORM THICKNESS, THE UPPER AND LOWER ENDS OF EACH LEG COMPONENT BEING SECURED TO THE ADJACENT ENDS OF THE UPPER AND LOWER YOKE COMPONENTS, RESPECTIVELY, THE UPPER END OF EACH LEG COMPONENT HAVING A PORTION WHICH IS ADAPTED TO SEPARABLY INTERLOCK WITH A COMPLEMENTARY PORTION AT THE ADJACENT END OF THE ADJACENT UPPER YOKE COMPONENT, EACH PAIR OF COMPLEMENTARY INTERLOCKING PORTIONS OF SAID COMPONENTS LYING WITHIN THE PLANES OF THE PLATE SURFACES OF SAID FRAME AND BEING SEPA- 